MRAM devices based on spin transfer torque (STT) are popular forms of non-volatile memory due to their low power consumption, high storage capacity and high operational speed. The microprocessor industry continues to advance the goal of smaller, more efficient microprocessors, such as MRAM devices, which are capable of integration within a variety of applications without compromising performance or cost. The memory storage element of a MRAM device is known as a magnetic tunnel junction (MTJ), which is magnetically controlled (switched) to enable a read or write operation.
Unfortunately, the current STT-MRAM devices are subject to seal ring peeling defect due to 2× via (WT) bar punch through to an underlying metallization layer (M3 or M5) at a seal ring area. In FIG. 1, the memory region A and logic region B of a conventional STT-MRAM device is illustrated in cross-section. The M3 layer 101 is formed in a low dielectric constant (low-k) dielectric layer 103 in both the memory region A and logic region B. The WT 105 connects the 2× metal layer (BA) loop 107 to the M3 101 in the seal ring area of logic region B The seal ring enclose the active area. The seal ring structure includes an inner seal ring portion surrounding an integrated circuit region, to protect circuit. In the memory region A, the tunnel junction via 109 connects the BA 107 to the underlying MTJ 111. The WT 105 is formed in a low temperature tetraethyl orthosilicate (TEOS) 113 in the logic region B, and the MTJ 111 is formed in the low temperature TEOS 113 in the memory region A. It is difficult to achieve proper landing at both the seal ring and logic area B from the WT 105 etch tuning due to a significant etch rate difference between the seal ring and logic area B. Seal ring peeling defect 115 is shown due to WT 105 bar punch through to M3 101 at a seal ring area. The punch through etch extends down to the M3 layer 115a. 
A need therefore exists for a method for forming a MRAM device which prevents WT etch punch through and seal ring peeling, and the resulting device.